In the interest of sparing you the same aggravation, here’s what you need to do that Apple fails to clarify:

• Open one PDF in Preview, then drag the other PDF from the Finder into that window. Apple’s online help is correct through this step.

• Do not try to save the combined PDF. Do not use the File menu’s “Export as PDF…” command. Both will leave you with a document consisting only of the first PDF.

• Instead, go to the File menu, select “Print…” and then click the downward-facing button next to “PDF” at the lower-left corner. Select “Save as PDF…” and you will have your combined PDF file.

Dear Apple: When I gripe about the state of software quality on the Mac these days, it’s things like this that usually set me off. Here we have a completely unintuitive process in which the correct way to do things sits three clicks deep in the app’s UI–and two clicks further in than the menu options that look like they’d do the job. And I know I’m not the only user irked by it.